About to upgrade from Intel Gen 4 to Gen 8

I'm trying to back up my Windows drive, but for the life of me I can't figure out why it's including another drive that I use for temp files. I can't untick it either it says it's required by Windows.

I was also thinking about taking my chances on going into safe mode removing all chipset drivers etc... I'm trying keep my registery and of course my documents. I have a few obsolete programs that if I actually do a fresh install I will not be able to use them or get the program. Would backing up registery and then importing it work?